JP4600384B2 - Manufacturing method of honeycomb structure - Google Patents

Description

  The present invention relates to a method for manufacturing a honeycomb structure.

  Conventionally, a method for manufacturing a ceramic honeycomb structure has been proposed in Patent Document 1, for example. In this Patent Document 1, an extrusion step of forming a honeycomb formed body from a ceramic material obtained by kneading raw material powder and water, a cutting step of cutting the honeycomb formed body into a certain length, and drying the cut honeycomb formed body There has been proposed a method of manufacturing a ceramic honeycomb structure by sequentially performing a drying step of firing and a firing step of firing the dried honeycomb formed body.

In the drying step among the above steps, the honeycomb formed body is dried while the honeycomb formed body is conveyed by a belt conveyor. In the firing step, the ceramic honeycomb structure is manufactured by firing the honeycomb formed body using a firing apparatus configured to fire the honeycomb formed body in a firing furnace.
JP 2003-145521 A

  However, when the honeycomb formed body is fired by the firing process in the above-described conventional technique, for example, in the drying process, the honeycomb formed body is transported one after another into the firing furnace of the firing apparatus by the transport as in the method of transporting the honeycomb formed body by the belt conveyor. When the honeycomb formed body is carried in, the number of honeycomb formed bodies in the furnace in a certain time may not be constant. This is because, for example, when a plurality of workpieces that are honeycomb formed bodies are mounted on a cart and carried into a firing furnace, a difference occurs in the number of workpieces mounted on each cart by removing the defective workpiece from the cart. is there.

  In addition, when carrying a trolley | bogie in a baking furnace, it is possible to unify the number of the workpiece | work mounted in each trolley | bogie. However, after the honeycomb molded body that has been molded and cut in the extrusion process and the cutting process is placed on each carriage in a certain quantity, defective ones are removed for each carriage, and each carriage is carried directly into the firing furnace. Therefore, the workpiece cannot be transferred to another cart, and the number of workpieces mounted cannot be made constant for each cart.

  Moreover, the firing profile of the firing furnace (the relationship between the position in the firing furnace and the firing temperature) is created according to the number of workpieces carried into the firing furnace. That is, by varying the heat capacity (physical quantity corresponding to the temperature received by the workpiece) in the firing furnace according to the number of workpieces, a firing profile for each quantity of workpieces is required. However, if the number of workpieces in the firing furnace is not constant due to the difference in the number of workpieces mounted on each carriage as described above, a pre-baked firing is performed to adjust the temperature in the firing furnace. It is necessary to switch to a firing profile according to the number of workpieces in the furnace.

  For example, when the firing profile is switched in a firing furnace in which the temperature is divided for each zone, the firing profile is switched because the temperature in the firing furnace is difficult to change and the responsiveness to the heat capacity of the workpiece is poor. It takes time to adjust the temperature in the furnace. For this reason, the variation in the temperature distribution of the entire firing furnace becomes large, and the variation in the heat capacity given to each workpiece on each carriage causes variations in the quality and finish of the workpiece fired for each carriage.

  In view of the above points, it is an object of the present invention to reduce workpiece quality variations and finish variations even when the number of workpieces carried into a firing furnace varies when a fired body is manufactured.

  In order to achieve the above object, the present invention provides a firing profile showing the relationship between the position in the firing furnace (30, 40) and the temperature used when firing the workpiece (20) in the firing furnace (30, 40). It is characterized by creating.

  That is, first, the workpiece (20) is formed and placed on the carriage (10) having a fixed load, and defective ones of the workpieces (20) are removed. And the weight of each trolley | bogie (10) is kept constant by adding the weight which removed the bad workpiece | work (20) to the trolley | bogie (10). Furthermore, a heat capacity measuring means (14) for measuring the maximum heat capacity received by each carriage (10) in the firing furnace (30, 40) is installed in each carriage (10).

  Thereafter, each carriage (10) is carried into the firing furnace, and the inside of the firing furnace (30, 40) is used with a firing profile corresponding to the number of workpieces (20) carried into the firing furnace (30, 40). The workpiece (20) is fired while changing the temperature.

  Subsequently, the heat capacity received by each carriage (10) is obtained from each heat capacity measuring means (14) installed in each carriage (10). When the heat capacity is expressed by the sum of the reference value indicating the heating temperature to be applied to each workpiece (20) in the firing furnace (30, 40) and the deviation from the reference value, the deviation from the reference value is indicated for each carriage. It acquires from each heat capacity of (10). The firing profile that realizes the heat capacity applied to the carriage (10) that shows the smallest deviation from each reference value thus obtained is defined as a firing profile for firing the workpiece (20).

  The fired profile obtained in this way is used for manufacturing the workpiece (20). As a result, even if the number of workpieces (20) to be fired placed on each carriage (10) is different, the weight of each carriage (10) can be considered to be constant. The heat capacity given to 10) can be made constant. Therefore, the heat capacity given to each workpiece (20) of each carriage (10) can be made constant, and variations in quality (strength etc.) and finishes (appearance etc.) of the finished honeycomb structure can be reduced. be able to.

  In addition, when the honeycomb structure is manufactured by firing the workpiece (20) after the firing profile creation step, the firing profile acquired in the heat capacity adjustment step in the firing profile creation step is used as the firing furnace (30, 40). Even if the number of workpieces (20) carried in varies, it is used uniformly.

  Thereby, the temperature distribution in the firing furnace (30, 40) can be kept constant, and the same heat capacity can be given to each workpiece (20), so that variations in the quality and finish of the honeycomb structure can be reduced.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a honeycomb structure according to the first embodiment of the present invention. As shown in this figure, the honeycomb structure 1 has a cylindrical shape, and is configured, for example, as a sintered product of ceramics. The inside of such a honeycomb structure 1 has a honeycomb structure, and a large number of holes 4 penetrating both end faces 2 and 3 of the cylinder are formed in the axial direction of the cylinder constituting the honeycomb structure, so that it is configured as a so-called monolith. Has been. These numerous holes 4 form independent passages.

  Next, a method for manufacturing the honeycomb structure 1 will be described. When the honeycomb structure 1 is manufactured, a raw honeycomb formed body having the same shape as the honeycomb structure 1 is formed, and the honeycomb formed body is fired in a firing furnace, whereby the honeycomb structured body 1 is manufactured.

  As described above, when the honeycomb formed body is fired in the firing furnace, the honeycomb formed body is fired by giving a desired heat capacity (temperature), and thus a firing profile that represents the relationship between the position in the firing furnace and the temperature is necessary. is there. Hereinafter, a firing profile creation process for creating a firing profile will be described.

  First, an extrusion process for forming a honeycomb formed body is performed by extruding a ceramic material obtained by kneading the raw material to be the honeycomb structure 1 and water from a mold. Subsequently, a cutting process for cutting the honeycomb formed body into a certain length is performed to obtain a raw honeycomb formed body. Hereinafter, the honeycomb formed body divided individually by the cutting process is referred to as a workpiece.

  And the 1st drying process which dries a workpiece | work is performed and the water | moisture content of a workpiece | work is removed. Further, in this step, after finely adjusting the size of the workpiece to the target value by cutting the dried workpiece, a plurality of workpieces are placed on each cart.

  Thereafter, the defective product among the plurality of works placed on the carriage is removed from the carriage. For example, when a maximum of 48 workpieces are placed on the carriage, when a defective product is found from the 48 workpieces, the found defective product is removed from the carriage. Therefore, the number of workpieces obtained by removing defective products from the maximum number mounted is finally fired on the cart.

  2A and 2B are views showing a state in which a work is placed on the carriage, where FIG. 2A is a view of the carriage as viewed from the traveling direction of the carriage, and FIG. 2B is a view taken along arrow A in FIG. As shown in FIGS. 2 (a) and 2 (b), the pillars 11 are arranged on the carriage 10 at regular intervals, and the shelves 12 are arranged on the pillars 11, so that the workpiece 20 can be placed thereon. Shelf is configured. In the present embodiment, a maximum of 16 (4 × 4) workpieces are arranged on one shelf, and a three-stage shelf is configured so that a maximum of 48 workpieces 20 can be placed on the carriage 10. It has become.

  Further, as shown in FIG. 2 (b), in order to make the weight of each carriage 10 uniform, a dummy honeycomb fired body 13 that has already been fired is disposed at a place removed as a defect. Thereby, the weight of each cart 10 is made the same.

  A reference thermo 14 (corresponding to the heat capacity measuring means of the present invention) is also mounted on the carriage 10 on which the workpiece 20 is mounted as described above. This reference thermometer 14 measures the heat capacity received by the workpiece 20 in the firing furnace.

  The reference thermostat 14 has a rectangular parallelepiped shape made of alumina, for example, and has a property that its length is reduced according to the heat capacity of the reference thermostat 14. Since the reference thermostat 14 does not return to its original size once contracted, the maximum heat capacity received by the reference thermostat 14, that is, the maximum heat capacity received by the workpiece 20 can be known. When acquiring the heat capacity, a conversion table between the length of the reference thermo 14 and the heat capacity is known, and the heat capacity can be easily derived from the size of the reference thermo 14.

  Next, the 2nd drying process which heats and dries each workpiece | work 20 mounted in the trolley | bogie 10 is performed. In addition, the process from the said extrusion process to the said 2nd drying process is corresponded to the preparatory process of this invention.

  Then, the trolley | bogie 10 is carried in to a baking furnace, and the baking process which bakes the workpiece | work 20 is performed. First, the continuous firing furnace used in the firing step will be described. FIG. 3 is an overall schematic view of a continuous firing furnace. As shown in this figure, the continuous firing furnace 30 is of a tunnel type, and includes a first passage portion 31, a heating portion 32, and a second passage portion 33. In addition, the number described in each cart 10 in FIG. 3 is a cart number, for example. Moreover, although the width | variety in the advancing direction of each trolley | bogie 10 is drawn differently, the size of each trolley | bogie 10 is actually the same.

  Among these, the 1st channel | path part 31 and one of the heating parts 32 are connected, and the other of the heating part 32 and the 2nd channel | path part 33 are connected, The said trolley | bogie 10 moves to each inside. Each passage is provided.

  The heating unit 32 has a burner 34 in the passage, and a gas is supplied to the burner 34 through a gas pipe 35 so that fire is emitted from the burner 34. In addition, the burner 34 is arrange | positioned in the place where a fire does not hit directly on the workpiece | work 20 on the trolley | bogie 10. FIG. Moreover, the inside of the 1st channel | path part 31 and the 2nd channel | path part 33 is warmed by the residual heat of the fire of the burner 34 of the heating part 32. FIG.

  The opposite side of the first passage portion 31 to the heating portion 32 is a carry-in entrance, and the carriage 10 is pushed out by a hydraulic pusher (not shown) so that the carriage 10 is brought into the first passage portion 31 from the carry-in entrance. It comes to be brought in. Then, the bogie 10 is pushed out one after another by the hydraulic pusher, so that the bogie 10 previously carried into the continuous firing furnace 30 is pushed by the bogie 10 carried into the continuous firing furnace 30 later, so that the continuous firing furnace. Move in 30. In addition, the trolley | bogie 10 moves in the continuous baking furnace 30 over 70 hours, for example.

  In the present embodiment, the continuous firing furnace 30 is controlled by a control device (not shown). This control device is configured as a personal computer including, for example, a CPU, RAM, ROM, hard disk and the like, and the burning power stored in the hard disk is executed to control the heating power of the burner 34 and the like. Yes.

  In other words, the control device is provided with a firing profile corresponding to the number of workpieces 20 carried into the continuous firing furnace 30 when executing the firing program. This firing profile shows the relationship between the position in the continuous firing furnace 30 and the temperature, and includes the thermal power information of the burner 34 that realizes the relationship between the position in the continuous firing furnace 30 and the temperature.

  In the continuous firing furnace 30, a plurality of thermocouples are installed in the first passage portion 31 and the second passage portion 33, and for example, a plurality of radiation thermometers are installed in the heating portion 32, and a voltage difference from each thermocouple is generated. The voltage difference is converted into temperature by being input to the control device, and the temperature value is input to the control device from each radiation thermometer. Thereby, the temperature distribution in the continuous firing furnace 30 is acquired according to the heating power of the burner 34.

  Accordingly, the control device monitors the temperature of each thermocouple and each radiation thermometer and adjusts the heating power of the burner 34, thereby realizing the temperature distribution indicated by the selected firing profile in the continuous firing furnace. .

  A baking process is performed using the continuous baking furnace 30 which has the above structures. Specifically, each carriage 10 that has finished the second drying step is successively carried into the first passage portion 31 by a hydraulic pusher. At this time, for example, the firing profile in the case of the maximum number of workpieces 20 carried into the continuous firing furnace 30 is used.

  Then, each carriage 10 is successively carried into the continuous firing furnace 30 by the hydraulic pusher, whereby each carriage 10 passes through the first passage portion 31 and is guided into the heating portion 32. Thereby, the work 20 on the carriage 10 is fired by the heating unit 32, and the carriage 10 is carried out from the second passage portion 33.

  Subsequently, a variation in the heat capacity given to each cart 10 is examined, and a heat capacity adjustment step is performed to create a firing profile for giving a constant heat capacity to each cart 10 carried into the continuous firing furnace 30.

  For this reason, first, the length of the reference thermo 14 installed in each cart 10 is measured, and the heat capacity is obtained from the length of the reference thermo 14 using a conversion table. For example, the heat capacity based on the reference thermostat 14 is acquired for each of the 20 carts 10.

  A firing heat intensity is calculated | required from each heat capacity of each trolley | bogie 10 acquired as mentioned above. The firing temperature is a physical quantity indicating a temperature represented by the sum of the value of the heat capacity management standard and the deviation from the value of the heat capacity management standard. The value of the heat capacity management standard refers to the firing temperature of the workpiece 20 in the heating section 32 of the continuous firing furnace 30, and corresponds to the heating temperature to be given to each workpiece 20, for example, 1450 ° C.

  Therefore, the deviation from 1450 ° C. is acquired from each heat capacity of each carriage 10. It shows that the variation of the heat capacity given to the workpiece | work 20 mounted on the cart 10 is so large that the value of this deviation | shift is large.

  When firing the workpiece 20, the control device changes the firing profile according to the number of workpieces 20 on the carriage 10, and adjusts the heat capacity of the burner 34 to adjust the heat capacity in the heating unit 32. However, even if the heat capacity of the work 20 is given by the adjusted thermal power of the burner 34, the heat capacity actually received by the work 20 in the heating unit 32 must be confirmed by the reference thermostat 14 after being carried out of the continuous firing furnace 30. .

  In other words, it can be seen how much the heat capacity received by each carriage 10 is based on the value of the heat capacity management standard. As described above, the larger the deviation, the greater the variation in the heat capacity applied to the workpiece 20, which may cause a reduction in the quality of the finished product. Therefore, among the trolleys 10, the deviation of the heat capacity received in the continuous firing furnace 30 from the management standard value is the smallest heat capacity given to the trolley 10, that is, the maximum heat capacity of the trolleys 10. As described above, the heating power of the burner 34 is kept constant. Thereby, the weight of each cart 10 can be regarded as constant, and the heat capacity applied to each cart 10 can be made constant.

  The rate of change in heat capacity is preferably within 0.5%. If the rate of change of the heat capacity exceeds 2%, the finished product is likely to be defective in appearance, and a characteristic shift is likely to occur. Therefore, the firing profile can be made constant by keeping the rate of change of the heat capacity within the above numerical value.

  And the baking profile used as the heat capacity acquired as mentioned above is created, and it inputs into a control apparatus. Thus, the firing profile creation process ends. In the future, when manufacturing the honeycomb structure 1, in the firing step of firing the workpiece 20 in the continuous firing furnace 30, the carriage 10 is carried into the continuous firing furnace 30 and the number of the workpieces 20 in the continuous firing furnace 30 varies. Even so, the heating power of the burner 34 is adjusted only in accordance with the firing profile acquired in the heat capacity adjustment step, and the workpiece 20 is fired. That is, the honeycomb structure 1 shown in FIG. 1 is manufactured by sequentially performing the extrusion process, the cutting process, the first drying process, the second drying process, and the firing process.

  As described above, in the present embodiment, in the continuous firing furnace 30, in order to reduce the variation in the heat capacity given to each work 20 of each carriage 10, the heat capacity of the maximum load number of works of the carriage 10 is reduced. Thus, a firing profile in which the heating power of the burner 34 is set is created. Thereby, the weight of each cart 10 can be considered constant, and as a result, the heat capacity given to each cart 10 can be made constant.

  Therefore, even if the number of workpieces 20 mounted on each carriage 10 is different for each carriage 10, the same heat capacity can be given to each carriage 10, and variations in the quality of each workpiece 20 can be reduced. .

(Second Embodiment)
In the present embodiment, only different parts from the first embodiment will be described. The present embodiment is characterized in that the workpiece 20 is fired using a shuttle-type batch firing furnace instead of the tunnel-type continuous firing furnace 30.

  FIG. 4 is an overall schematic view of the batch firing furnace according to the present embodiment. As shown in this figure, the batch firing furnace 40 includes a firing furnace 41, a pipe 42, a processing furnace 43, and a chimney 44.

  The firing furnace 41 includes a sliding entrance door 41a, and each carriage 10 is carried into the firing furnace 41 as the entrance door 41a slides. In addition, a burner 34 is provided in the firing furnace 41, and each work 20 on each carriage 10 can be fired by generating fire from the burner 34. Further, exhaust is performed from the chimney 44 via the pipe 42 and the processing furnace 43.

  In the present embodiment, the heating power of the burner 34 is adjusted by the control device in accordance with the firing profile obtained in the same manner as in the first embodiment.

  In this way, the workpiece 20 may be fired using the batch firing furnace 40. Even in this case, a firing profile may be acquired in the same manner as in the first embodiment, and the workpiece 20 may be fired according to this firing profile.

(Other embodiments)
In each of the above embodiments, the honeycomb structure 1 is manufactured as a manufactured product. However, a plug material may be provided in each hole 4 of the honeycomb structure 1 to manufacture an exhaust gas purification filter. In this case, a step of providing a plug material in each hole of the workpiece 20 may be added, and the workpiece 20 with the plug material provided may be fired. Further, in addition to the honeycomb structure and the exhaust gas purification filter, the method shown in each of the above embodiments can be adopted when a ceramic product is fired in a firing furnace.

  Moreover, in each said embodiment, although the reference thermo 14 is used as what measures the largest heat capacity which the trolley | bogie 10 receives in the continuous baking furnace 30, it fell according to the heat capacity which the rod-shaped weight stood on the stand received You may use the Seegel which acquires the heat capacity which the weight received by measuring height.

  In each said embodiment, when the workpiece | work 20 mounted on the trolley | bogie 10 contains a defect, the honeycomb fired body 13 is laid on the trolley | bogie 10, However, Tochi of the same material as the workpiece | work 20 may be mounted.

1 is a perspective view of a honeycomb structure according to a first embodiment of the present invention. It is the figure which showed a mode that the workpiece | work was mounted on the trolley | bogie, (a) is the figure which looked at the trolley | bogie side from the advancing direction of a trolley | bogie, (b) is an A arrow view of (a). It is the whole continuous baking furnace schematic. It is the whole batch firing furnace schematic diagram concerning a 2nd embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Honeycomb structure, 2, 3 ... End face of honeycomb structure, 4 ... Cell, 10 ... Dolly, 14 ... Referrer thermostat, 20 ... Work, 30, 40 ... Firing furnace.

Claims (2)

A method for manufacturing a honeycomb structure having a column shape and having a large number of cells (4) penetrating both end surfaces (2, 3) of the column shape in an axial direction of the column shape,
When firing the workpiece (20) shaped like the honeycomb structure in the firing furnace (30, 40), the firing furnace (for the number of the works (20) carried into the firing furnace (30, 40) ( 30 and 40) A firing profile creation step for creating the firing profile in order to manufacture the honeycomb structure by heating the inside of the firing furnace (30 and 40) according to the firing profile indicating the relationship between the position in the interior and the temperature. Contains
The firing profile creation step includes
When a large number of the workpieces (20) are formed and the workpieces (20) are placed on the carts (10) having a fixed load, the defective workpieces are removed from the workpieces (20), and the defective workpieces are removed. The weight of each cart (10) is kept constant by adding the weight of (20) removed to the cart (10), and the calcining furnaces (30, 40) are further added to the cart (10). ), A preparatory step of installing heat capacity measuring means (14) for measuring the maximum heat capacity received by each of the carts (10),
After the preparation step, the carts (10) are carried into the firing furnace, and the firing profiles according to the number of the workpieces (20) carried into the firing furnace (30, 40) are used. A firing step of firing the workpiece (20) while changing the temperature in the firing furnace (30, 40);
The heat capacity received by each carriage (10) is obtained from each heat capacity measuring means (14) installed on each carriage (10) that has finished the firing step, and the heat capacity is obtained from the firing furnace (30, 40), when expressed as the sum of a reference value indicating the heating temperature to be applied to each workpiece (20) and a deviation from the reference value, the deviation from the reference value represents each heat capacity of each carriage (10). The firing profile that realizes the heat capacity applied to the carriage (10) showing the smallest deviation from each of the obtained reference values is set as a firing profile for firing each workpiece (20). A method for manufacturing a honeycomb structure, comprising: a heat capacity adjustment step. After the firing profile creation step, when the honeycomb structure is manufactured by firing the workpiece (20), the firing profile acquired in the heat capacity adjustment step in the firing profile creation step is used as the firing furnace ( 30. The method for manufacturing a honeycomb structured body according to claim 1, wherein the number of the workpieces (20) carried into the inside (30, 40) is uniform even if the number of the workpieces (20) varies.

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